Light-Controlled Anticancer Activity and Cellular Uptake of a Photoswitchable Cisplatin Analogue.

A photoactive analogue of cisplatin was synthesized with two arylazopyrazole ligands, able to undergo -/- photoisomerizations. The photoisomer showed a dark half-life of 9 days. The cytotoxicities of both photoisomers of the complex were determined in several cancer and normal cell lines and compared to that of cisplatin. The photoisomer of the complex was much more cytotoxic than both the photoisomer and cisplatin, and was more toxic for cancer (4T1) than for normal (NMuMG) murine breast cells. 4T1 cell death occurred through necrosis. Photoisomerization of the and photoisomers internalized by the 4T1 cells increased and decreased their viability, respectively. The cellular uptake of the photoisomer was stronger than that of both the photoisomer and cisplatin. Both photoisomers interacted with DNA faster than cisplatin. The photoisomer was bound stronger by bovine serum albumin and induced a greater decrease in cellular glutathione levels than the photoisomer.